Fathers are more than social accidents. Research has demonstrated that fathers matter to children's development. Despite noted progress, challenges remain on how best to conceptualize and assess fathering and father–child relationships. The current monograph is the result of an SRCD‐sponsored meeting of fatherhood scholars brought together to discuss these challenges and make recommendations for best practices for incorporating fathers in studies on parenting and children's development. The first aim of this monograph was to provide a brief update on the current state of research on fathering and to lay out a developmental ecological systems perspective as a conceptual framework for understanding the different spaces fathers inhabit in their children's lives. Because there is wide variability in fathers’ roles, the ecological systems perspective situates fathers, mothers, children, and other caregivers within an evolving network of interrelated social relationships in which children and their parents change over time and space (e.g., residence). The second aim was to present examples of empirical studies conducted by members of the international working group that highlighted different methods, data collection, and statistical analyses used to capture the variability in father–child relationships. The monograph ends with a commentary that elaborates on the ecological systems framework with a discussion of the broader macrosystem and social‐contextual influences that impinge on fathers and their children. The collection of articles contributes to research on father–child relationships by advancing theory and presenting varied methods and analysis strategies that assist in understanding the father–child relationship and its impact on child development.

Bipolar disorder (BD) is a serious mood disorder associated with circadian rhythm abnormalities. Risk for BD is genetically encoded and overlaps with systems that maintain circadian rhythms. Lithium is an effective mood stabilizer treatment for BD, but only a minority of patients fully respond to monotherapy. Presently, we hypothesized that lithium-responsive BD patients (Li-R) would show characteristic differences in chronotype and cellular circadian rhythms compared to lithium non-responders (Li-NR). Selecting patients from a prospective, multi-center, clinical trial of lithium monotherapy, we examined morning vs. evening preference (chronotype) as a dimension of circadian rhythm function in 193 Li-R and Li-NR BD patients. From a subset of 59 patient donors, we measured circadian rhythms in skin fibroblasts longitudinally over 5 days using a bioluminescent reporter (Per2-luc). We then estimated circadian rhythm parameters (amplitude, period, phase) and the pharmacological effects of lithium on rhythms in cells from Li-R and Li-NR donors. Compared to Li-NRs, Li-Rs showed a difference in chronotype, with higher levels of morningness. Evening chronotype was associated with increased mood symptoms at baseline, including depression, mania, and insomnia. Cells from Li-Rs were more likely to exhibit a short circadian period, a linear relationship between period and phase, and period shortening effects of lithium. Common genetic variation in the IP 3 signaling pathway may account for some of the individual differences in the effects of lithium on cellular rhythms. We conclude that circadian rhythms may influence response to lithium in maintenance treatment of BD.

Using data from a diverse sample of low-income families who participated in the Early Head Start Research Evaluation Project (n = 73), we explored the association between mothers' and fathers' playfulness with toddlers, toddler's affect during play, and children's language and emotion regulation at prekindergarten. There were two main findings. First, fathers' playfulness in toddlerhood was associated with children's vocabulary skills in prekindergarten whereas mothers' playfulness was related to children's emotion regulation. Cross-parental effects were found only for mothers. The association between mothers' playfulness and children's vocabulary and emotion regulation was strengthened when fathers engaged in more pretend play and when children were affectively positive during the play. These findings show that playfulness is an important source of variation in the vocabulary and emotion regulation of children growing up in low-income families. They also point to domain-specific ways that mothers and fathers promote children's regulatory and vocabulary skills, and highlight the importance of children's positive engagement in play.

Using data from a racially and ethnically diverse sample of low-income fathers and their 2-year-old children who participated in the Early Head Start Research Evaluation Project (n = 80), the current study explored the association among paternal depressive symptoms and level of education, fathers’ language to their children, and children’s language skills. There were three main findings. First, there was large variability in the quality and quantity of language used during linguistic interactions between low-income fathers and their toddlers. Second, fathers with higher levels of education had children who spoke more (i.e. utterances) and had more diverse vocabularies (i.e. word types) than fathers with lower levels of education. However, fathers with more depressive symptoms had children with less grammatically complex language (i.e. smaller MLUs) than fathers with fewer depressive symptoms. Third, direct effects between fathers’ depressive symptoms and level of education and children’s language outcomes were partially mediated by fathers’ quantity and quality of language.

ClinicalTrials.gov identifier: NCT00671853.